Collision determination device

ABSTRACT

A collision determination device determines the possibility of collision between a host vehicle and the other object on the basis of a shortest arrival time calculated by a shortest arrival time calculation unit and a passage time at each point of the host vehicle acquired by a vehicle route candidate acquisition unit. In this way, even if a locus to be taken by the other object is not generated, the shortest arrival time at which the other object can arrive at each point of the route candidate of the host vehicle with a predetermined first displacement is calculated, thereby determining the possibility of collision between the host vehicle and the other object. Therefore, it is possible to reduce a computational load for determining collision and to accurately determine collision between the host vehicle and the other object.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a national phase application of InternationalApplication No. PCT/JP2010/067450, filed Oct. 5, 2010, the content ofwhich is incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a collision determination device.

BACKGROUND ART

In the related art, as a route evaluation device which evaluates a routeof a mobile object, a route setting device which evaluates and sets aroute to be taken by a specific object from among a plurality of objectsis known (for example, see Japanese Patent No, 4353192). In the routesetting device, change in a position to be taken by each of a pluralityof objects over time is generated as a spatiotemporal locus constitutedby time and space. The routes of a plurality of objects are predictedusing the locus, and the degree of interference between a route to betaken by a specific object and a route to be taken by the other objectis quantitatively calculated on the basis of the prediction result. Aroute on which the specific object is most unlikely to interfere withthe other object is determined as a route which should be taken by thespecific object.

CITATION LIST Patent Literature

-   [Patent Literature 1] Japanese Patent No, 4353192

SUMMARY OF INVENTION Technical Problem

On the other hand, although in the route setting device of the relatedart, a locus of an object is generated, and the degree of interferenceis calculated on the basis of the route of the object predicted by thelocus, the traveling efficiency of the host vehicle is not taken intoconsideration. If control is performed taking into consideration thetraveling efficiency of the host vehicle in the route setting device ofthe related art, a processing load increases with an increase in theamount of computation, and realizability is lacking. Accordingly, inorder to secure the traveling efficiency of the host vehicle whileavoiding collision, it is necessary to make a further improvement withrespect to the processing load.

The invention has been accomplished in order to solve theabove-described problems, and an object of the invention is to provide acollision determination device capable of reducing a processing loadwhile avoiding collision with the other object.

Solution to Problem

In order to solve the above-described problems, a collisiondetermination device according to an aspect of the invention includesvehicle route candidate acquisition means for acquiring a routecandidate of a host vehicle, other object status acquisition means foracquiring the status of the other object, shortest arrival timecalculation means for calculating a shortest arrival time, at which theother object can arrive at each point of the route candidate of the hostvehicle acquired by the vehicle route candidate acquisition means whenmoving with a predetermined first displacement, on the basis of thestatus of the other object acquired by the other object statusacquisition means, and collision determination means for determining thepossibility of collision between the host vehicle and the other objecton the basis of the shortest arrival time calculated by the shortestarrival time calculation means and the passage time at each point of theroute candidate of the host vehicle.

In the collision determination device, the possibility of collisionbetween the host vehicle and the other object is determined on the basisof the shortest arrival time calculated by the shortest arrival timecalculation means and the passage time at each point of the routecandidate of the host vehicle acquired by the vehicle route candidateacquisition means. In this way, even if a locus to be taken by the otherobject is not generated, the shortest arrival time at which the otherobject can arrive at each point of the route candidate of the hostvehicle with the predetermined first displacement is obtained, wherebythe possibility of collision between the host vehicle and the otherobject can be determined. Therefore, it is possible to reduce acomputational load for determining collision and to accurately determinecollision between the host vehicle and the other object. In this way, inthe collision determination device, it is possible to reduce aprocessing load while avoiding collision with the other object.

It is preferable that, when the shortest arrival time calculated by theshortest arrival time calculation means is smaller than the passage timeat each point of the route candidate of the host vehicle, the collisiondetermination means determines that there is a possibility that the hostvehicle collides with the other object. When the shortest arrival timeis greater than the passage time at each point of the route candidate ofthe host vehicle, collision between the host vehicle and the otherobject is avoided. Therefore, with the use of the relationship that theshortest arrival time is smaller than the passage time at each point ofthe route candidate of the host vehicle (shortest arrival time<passagetime), it is possible to more appropriately determine the possibility ofcollision between the other object and the host vehicle.

It is preferable that, when the shortest arrival time calculated by theshortest arrival time calculation means is smaller than the passage timeat each point of the route candidate of the host vehicle, and when thespeed of the host vehicle is higher than a predetermined speed, thecollision determination means determines that there is a possibilitythat the host vehicle collides with the other object. With thisconfiguration, since the traveling status of the host vehicle is takeninto consideration so as to determine the possibility of collision, itis possible to more accurately determine the possibility of collisionbetween the host vehicle and the other object.

It is preferable that the collision determination device furtherincludes longest stopover time calculation means for calculating alongest stopover time, at which the other object passes through eachpoint of the route candidate of the host vehicle acquired by the vehicleroute candidate acquisition means when reducing speed with apredetermined second displacement, on the basis of the status of theother object acquired by the other object status acquisition means,wherein, when the shortest arrival time calculated by the shortestarrival time calculation means is smaller than the passage time at eachpoint of the route candidate of the host vehicle, and the longeststopover time calculated by the longest stopover time calculation meansis greater than the passage time at each point of the route candidate ofthe host vehicle, the collision determination means determines thatthere is a possibility that the host vehicle collides with the otherobject. With this configuration, since the possibility of collision isdetermined on the basis of a plurality of movement statuses of the otherobject, it is possible to determine the possibility of collision betweenthe host vehicle and the other object with higher precision. As aresult, it is possible to improve reliability. The “longest stopovertime at which the other object passes through each point” represents thelatest time at which the other object passes by each point.

It is preferable that the collision determination device furtherincludes route candidate correction means for correcting the routecandidate of the host vehicle acquired by the vehicle route candidateacquisition means to a route candidate when the host vehicle takesavoidance behavior from a predetermined point, wherein the shortestarrival time calculation means calculates the shortest arrival time atwhich the other object arrives at each point of the route candidate ofthe host vehicle corrected by the route candidate correction means whenmoving with a predetermined first displacement, and when the shortestarrival time calculated by the shortest arrival time calculation meansis smaller than the time at which the other object passes through eachpoint of the route candidate of the host vehicle corrected by the routecandidate correction means, the collision determination means determinesthat there is a possibility that the host vehicle collides with theother object. With this configuration, for example, when passing by animmediate pedestrian as the other object, since failure of selection ofonly a route candidate in which the host vehicle starts to reduce speedfrom the front side of the position of the pedestrian is avoided, it ispossible to maintain the traveling efficiency of the host vehicle. Here,“to take avoidance behavior” includes behavior, such as reduction inspeed, increase in speed, or steering.

It is preferable that the longest stopover time calculation meanscalculates the longest stopover time at which the other object passesthrough each point of the route candidate of the host vehicle correctedby the route candidate correction means when reducing speed with apredetermined second displacement, and when the shortest arrival timecalculated by the shortest arrival time calculation means is smallerthan the time at which the other object passes through each point of theroute candidate of the host vehicle corrected by the route candidatecorrection means, and when the longest stopover time calculated by thelongest stopover time calculation means is greater than the time at eachpoint of the route candidate of the host vehicle, the collisiondetermination means determines that there is a possibility that the hostvehicle collides with the other object. With this configuration, sincethe possibility of collision is determined on the basis of a pluralityof movement statuses of the other object, it is possible to determinethe possibility of collision between the host vehicle and the otherobject with higher precision. As a result, it is possible to improvereliability.

Advantageous Effects of Invention

According to the aspect of the invention, it is possible to reduce aprocessing load while avoiding collision with the other object.Therefore, it is possible to secure the traveling efficiency of the hostvehicle.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram showing the configuration of a collisiondetermination device according to a first embodiment.

FIG. 2 is a flowchart showing the operation of the collisiondetermination device.

FIG. 3 is a diagram illustrating the operation of the collisiondetermination device.

FIG. 4 is a diagram illustrating the operation of the collisiondetermination device.

FIG. 5 is a flowchart showing another operation of the collisiondetermination device.

FIG. 6 is a diagram illustrating another operation of the collisiondetermination device.

FIG. 7 is a diagram illustrating another operation of the collisiondetermination device.

FIG. 8 is a block diagram showing the configuration of a collisiondetermination device according to a second embodiment.

FIG. 9 is a diagram illustrating the operation of the collisiondetermination device according to the second embodiment.

FIG. 10 is a flowchart showing the operation of the collisiondetermination device according to the second embodiment.

DESCRIPTION OF EMBODIMENTS

Hereinafter, preferred embodiments of the invention will be describedwith reference to the drawings.

First Embodiment

FIG. 1 is a block diagram showing the configuration of a collisiondetermination device according to a first embodiment of the invention.As shown in FIG. 1, a collision determination device 1 includes avehicle route candidate acquisition unit (vehicle route candidateacquisition means) 11, a mobile object status acquisition unit (otherobject status acquisition means) 12, a mobile object determination unit13, a mobile object route candidate generation unit 14, a shortestarrival time calculation unit (shortest arrival time calculation means)15, a longest stopover time calculation unit (longest stopover timecalculation means) 16, and a collision determination unit (collisiondetermination means) 17. The collision determination device 1 is anelectrical control unit (ECU) which has a central processing unit (CPU)performing computation, a read only memory (ROM) storing a program orthe like for causing the CPU to execute respective processing, a randomaccess memory (RAM) storing various kinds of data, such as thecomputation result, and the like.

The vehicle route candidate acquisition unit 11 acquires a routecandidate of the host vehicle. The route candidate of the host vehicleis a future route candidate which is generated from information, such asthe position, speed, and direction of the host vehicle, by a routecandidate generation unit, and preferably includes information of eachpoint (position: x,y) of the host vehicle at a certain time (t). Thevehicle route candidate acquisition unit 11 outputs host vehicle routecandidate information representing the acquired route candidate of thehost vehicle to the shortest arrival time calculation unit 15, thelongest stopover time calculation unit 16, and the collisiondetermination unit 17. In regard to the route candidate, similarinformation can be output by appropriate calculation processing frominformation of the position (x,y) and the speed (Vx,Vy).

The mobile object status acquisition unit 12 acquires a present statusof a mobile object. The mobile object is a pedestrian (including abicycle), the other vehicle, or the like, and the present status of themobile object is information necessary for calculating the time untilthe mobile object reaches at a certain time, and is preferably theposition, speed, and direction of the mobile object, an acceleration, ayaw rate, a tire angle, or the like. Of course, when an appropriateassumption is placed on the mobile object, part of these kinds ofinformation can be omitted. The mobile status may be detected fromambient information including an object in the vicinity of the hostvehicle, the position of the other vehicle, or the like, or may bedetected by vehicle-to-vehicle communication or the like. The mobileobject status acquisition unit 12 outputs mobile object statusinformation representing the acquired status of the mobile object to theshortest arrival time calculation unit 15 and the longest stopover timecalculation unit 16. The ambient information including the object in thevicinity of the host vehicle, the position of the other vehicle, or thelike is acquired by a traveling status acquisition unit (not shown). Thetraveling status acquisition unit acquires a traveling status includingvehicle traveling information, such as the vehicle speed or the steeringangle, the ambient information, such as the object in the vicinity ofthe host vehicle or the position and speed of the other vehicle, andtraveling road information, such as a map.

The mobile object determination unit 13 determines how a mobile objectmoves from now. For example, the mobile object determination unit 13executes image processing on the basis of image information of an imagephotographed by a camera mounted in the host vehicle and determineswhether a mobile object is a pedestrian or a vehicle. When it isdetermined that a mobile object is a vehicle, it is hereinafter regardedthat the mobile object comparatively observes a condition (trafficclassification, road direction, or the like) that the movement of themobile object is permitted. When it is determined that the mobile objectis a pedestrian, it is hereinafter regarded that the mobile object doesnot comparatively observe a condition (traffic classification, roaddirection, or the like) that the movement of the mobile object ispermitted. The mobile object determination unit 13 outputs determinationresult information representing the determination result to the mobileobject route candidate generation unit 14, the shortest arrival timecalculation unit 15, and the longest stopover time calculation unit 16.The determination of the mobile object may be performed on the basis ofthe previous motions of the mobile object. As the type of the mobileobject, a vehicle (for example, a two-wheeled vehicle) which does notcomparatively observe a condition that the movement is permitted, apedestrian who observes the condition, or the like may be determined.

The mobile object route candidate generation unit 14 calculates a routecandidate of a mobile object. If the determination result informationoutput from the mobile object determination unit 13 is received, whenthe determination result information represents that the mobile objectis the other vehicle (vehicle), the mobile object route candidategeneration unit 14 calculates a road network (route candidate)representing the integrated state of a road which the other vehicleshould follow on the basis of information regarding the shape or thelike of a road in the vicinity of the other vehicle. The mobile objectroute candidate generation unit 14 outputs mobile object routeinformation representing the calculated route candidate of the mobileobject to the shortest arrival time calculation unit 15 and the longeststopover time calculation unit 16.

The shortest arrival time calculation unit 15 calculates the shortestarrival time at which the mobile object arrives at each point of theroute candidate of the host vehicle when moving from an initial speedwith a predetermined first displacement. If the mobile object statusinformation output from the mobile object status acquisition unit 12 isreceived and the determination result information output from the mobileobject determination unit 13 is received, when the determination resultinformation represents that the mobile object is a pedestrian, theshortest arrival time calculation unit 15 calculates the shortestarrival time t_(min) at which the mobile object can arrive at each pointof the route candidate of the host vehicle when increasing speed fromthe initial speed to a predetermined maximum speed at a predeterminedacceleration (first displacement: for example, 0.3 G). The shortestarrival time calculation unit 15 provides information relating to thecalculated shortest arrival time t_(min) to road data and outputs roaddata information relating to road data to the collision determinationunit 17.

When the determination result information represents that the mobileobject is a vehicle, the shortest arrival time calculation unit 15calculates the shortest arrival time t_(min), at which the mobile objectcan arrive at each point of the road network of the mobile object whenincreasing speed from the initial speed to a predetermined maximum speed(a maximum speed provided to the road network+α) at a predeterminedacceleration, on the basis of the mobile object route information outputfrom the mobile object route candidate generation unit 14. The shortestarrival time calculation unit 15 provides information relating to thecalculated shortest arrival time t_(min) to the road network and outputsroad network information relating to the road network to the collisiondetermination unit 17.

The longest stopover time calculation unit 16 calculates the longeststopover time (the latest time at which the mobile object passes by eachpoint) at which the mobile object passes through each point of the routecandidate of the host vehicle when reducing speed from the initial speedwith a predetermined second displacement. If the mobile object statusinformation output from the mobile object status acquisition unit 12 isreceived and the determination result information output from the mobileobject determination unit 13 is received, when the determination resultinformation represents that the mobile object is a pedestrian, for eachpoint of the route candidate of the host vehicle, the longest stopovertime calculation unit 16 calculates the longest stopover time t_(max) atwhich the mobile object passes through each point of the route candidateof the host vehicle when reducing speed from the initial speed to apredetermined minimum speed at a predetermined deceleration (seconddisplacement: for example, −0.3 G). The longest stopover timecalculation unit 16 provides information relating to the calculatedlongest stopover time t_(max) to road data and outputs road datainformation relating to road data to the collision determination unit17.

When the determination result information represents that the mobileobject is a vehicle, for each point of the road network of the mobileobject, the longest stopover time calculation unit 16 calculates thelongest stopover time t_(max), at which the mobile object passes througheach point of the road network when reducing speed from the initialspeed to a predetermined minimum speed (a minimum speed provided to theroad network−β) at a predetermined deceleration, on the basis of themobile object route information output from the mobile object routecandidate generation unit 14. The longest stopover time calculation unit16 provides information relating to the calculated longest stopover timet_(max) to the road network and outputs road network informationrelating to the road network to the collision determination unit 17. Thelongest stopover time calculation unit 16 sets the longest stopover timet_(max) to be infinite (t_(max)=∞) when the mobile object can stop infront of a certain point and does not pass through this point.

The collision determination unit 17 determines the possibility ofcollision between the host vehicle and the mobile object. The collisiondetermination unit 17 receives the route candidate information outputfrom the vehicle route candidate acquisition unit 11 and the road datainformation output from the shortest arrival time calculation unit 15and the longest stopover time calculation unit 16. The collisiondetermination unit 17 determines whether or not the passage time t atwhich the host vehicle passes through each point (x,y,t) of the routecandidate represented by the route candidate information is greater thanthe shortest arrival time t_(min) represented by the shortest arrivaltime information and smaller than the time t_(max) represented by thelongest stopover time information (t_(min)<t<t_(max)), and determineswhether or not the speed V of the host vehicle is V>V_(m). When it isdetermined that t_(min)<t<t_(max) and V>V_(m), the collisiondetermination unit 17 determines that there is the possibility ofcollision between the host vehicle and the pedestrian, and outputsdetermination result information representing the effect. Note thatV_(m) is a value which is arbitrarily set and is preferably “0”.

If the route candidate information output from the vehicle routecandidate acquisition unit 11 and the road network information outputfrom the shortest arrival time calculation unit 15 and the longeststopover time calculation unit 16 are received, when the position of thehost vehicle interferes with the road network of the other vehicle, thecollision determination unit 17 determines whether or not the passagetime t at which the host vehicle passes through this point is greaterthan the shortest arrival time t_(m), and smaller than the longeststopover time t_(max) (t_(min)<t<t_(max)). When it is determined thatt_(min)<t<t_(max), the collision determination unit 17 determines thatthere is the possibility of collision between the host vehicle and theother vehicle, and outputs determination result information representingthe effect. The output determination result information is received by,for example, a traveling status setting device. In the traveling statussetting device, the best vehicle route candidate is selected on thebasis of the determination result information of a plurality of vehicleroute candidates, and a control signal is output to a driving controlunit (not shown) or a steering control unit (not shown).

Subsequently, the operation of the collision determination device 1 willbe described with reference to FIGS. 2 to 4. Initially, a case where themobile object is a pedestrian will be described. FIG. 2 is a flowchartshowing the operation of the collision determination device, and FIGS. 3and 4 are diagrams illustrating the operation of the collisiondetermination device.

As shown in FIG. 3, first, a route candidate of the host vehicle isacquired by the vehicle route candidate acquisition unit 11 (Step S01).Next, the initial state (position, speed, direction, and the like) of apedestrian (mobile object) is acquired by the mobile object statusacquisition unit 12 (Step S02). Subsequently, the shortest arrival timet_(min) is calculated by the shortest arrival time calculation unit 15(Step S03). The longest stopover time t_(max) is calculated by thelongest stopover time calculation unit 16 (Step S04), and informationrelating to the shortest arrival time t_(min) and the longest stopovertime t_(max) is provided to road data. Specifically, as shown in FIG.3A, in a pedestrian H, the shortest arrival time t_(min)=1, 2, 3, . . .is calculated as the shortest arrival time t_(min) for each point of theroad. As shown in FIG. 3B, in the pedestrian H, the longest stopovertime t_(max)=1, 2, 3, . . . , ∞ is calculated as the longest stopovertime t_(max) for each point of the road. FIG. 3B shows only the longeststopover time t_(max)=1.

The determination on the possibility of collision is made by thecollision determination unit 17 on the basis of road data, to which theshortest arrival time t_(min) calculated by the shortest arrival timecalculation unit 15 and the longest stopover time t_(max) calculated bythe longest stopover time calculation unit 16 are provided, and thepassage time t at each point of the route candidate of the host vehicleacquired by the vehicle route candidate acquisition unit 11 (Step S05),and it is determined whether or not t_(min)<t<t_(max) and V>V_(m) (StepS06).

Specifically, as shown in FIG. 4, for example, when a host vehicle Mpasses through a point “A”, since the passage time t_(A) is smaller thanthe shortest arrival time t_(min) (t_(A)<t_(min)), it is determined thatthere is no possibility of collision between the pedestrian H and thehost vehicle M. For example, when the host vehicle M passes through apoint “B”, since the passage time t_(B) is greater than the shortestarrival time t_(min) and smaller than the longest stopover time t_(max),and V>V_(m) (t_(min)<t<t_(m), V>V_(m)), it is determined that there isthe possibility of collision between the pedestrian H and the hostvehicle M. In Step S05, when it is determined that t_(min)<t<t_(max) andV>V_(m), the determination result representing the effect is output(Step S07). In Step S06, when it is determined that t_(min)<t<t_(max)and V>V_(m) are not established, the processing ends.

Next, a case where the mobile object is the other vehicle will bedescribed. FIG. 5 is a flowchart showing the operation of the collisiondetermination device, and FIGS. 6 and 7 are diagrams illustrating theoperation of the collision determination device.

As shown in FIG. 5, first, a route candidate of the host vehicle isacquired by the vehicle route candidate acquisition unit 11 (Step S11).Next, the initial state (position, speed, direction, and the like) ofthe other vehicle (mobile object) is acquired by the mobile objectstatus acquisition unit 12 (Step S12). Subsequently, the shortestarrival time t_(min) is calculated by the shortest arrival timecalculation unit 15 (Step S13). The longest stopover time t_(max) iscalculated by the longest stopover time calculation unit 16 (Step S14),and information relating to the shortest arrival time t_(min) and thelongest stopover time t_(max) is provided to the road network.Specifically, as shown in FIG. 6A, in the other vehicle M2, the shortestarrival time t_(min)=1, 2, 3, 4, 5, . . . is calculated as the shortestarrival time t_(min) for each point of the road network in the routecandidate of the other vehicle M2. As shown in FIG. 6B, in the othervehicle M2, the longest stopover time t_(max)=1, 2, 3, . . . , ∞ iscalculated as the longest stopover time t_(max) for each point of theroad network in the route candidate of the other vehicle M2.

The determination on the possibility of collision is made by thecollision determination unit 17 on the basis of the road network, towhich the shortest arrival time t_(min) calculated by the shortestarrival time calculation unit 15 and the longest stopover time t_(max)calculated by the longest stopover time calculation unit 16 areprovided, and the passage time t at each point of the route candidate ofthe host vehicle (Step S15), and it is determined whether or nott_(min)<t<t_(max) (Step S16).

Specifically, as shown in FIG. 7, for example, when the host vehicle Mpasses through a point “A”, since the passage time t_(A) is smaller thanthe shortest arrival time t_(min) (t_(A)<t_(min)), it is determined thatthere is no possibility of collision between the other vehicle M2 andthe host vehicle M. For example, when the host vehicle M passes througha point “B”, since the passage time t_(B) is greater than the shortestarrival time t_(min) and smaller than the longest stopover time t_(max)(t_(min)<t<t_(max)), it is determined that there is the possibility ofcollision between the other vehicle M2 and the host vehicle M. In StepS16, when it is determined that t_(min)<t<t_(max), the determinationresult representing the effect is output (Step S17). In Step S15, whenit is determined that t_(min)<t<t_(max) is not established, theprocessing ends.

As described above, in the collision determination device 1, thepossibility of collision between the host vehicle and the other objectis determined on the basis of the shortest arrival time t_(min)calculated by the shortest arrival time calculation unit 15 and thepassage time t at each point of the host vehicle acquired by the vehicleroute candidate acquisition unit 11. In this way, even if a locus to betaken by the other object is not generated, the shortest arrival time atwhich the other object can arrive at each point of the route candidateof the host vehicle with a predetermined first displacement is obtained,whereby it is possible to determine the possibility of collision betweenthe host vehicle and the other object. Therefore, it is possible toreduce a computational load for determining collision and to accuratelydetermine collision between the host vehicle and the other object. Inthis way, in the collision determination device, it is possible toreduce a processing load while avoiding collision with the other object.

When the shortest arrival time t_(min) calculated by the shortestarrival time calculation unit 15 is smaller than the passage time t ateach point of the route candidate of the host vehicle, the collisiondetermination unit 17 determines that there is the possibility ofcollision between the host vehicle and the other object. When theshortest arrival time t_(min) is smaller than the passage time t at eachpoint of the route candidate of the host vehicle, collision between thehost vehicle and the other object is avoided. Therefore, with the use ofthe relationship in which the shortest arrival time t_(min) is smallerthan the passage time t at each point of the route candidate of the hostvehicle (shortest arrival time t_(min)<passage time t), it is possibleto more appropriately determine the possibility of collision between theother object and the host vehicle.

When the shortest arrival time t_(min) calculated by the shortestarrival time calculation unit 15 is smaller than the passage time t ateach point of the route candidate of the host vehicle, and the speed Vof the host vehicle is higher than a predetermined speed V_(m), thecollision determination unit 17 determines that there is the possibilityof collision between the host vehicle and the other object. With thisconfiguration, since the traveling status of the host vehicle is takeninto consideration so as to determine the possibility of collision, itis possible to more accurately determine the possibility of collisionbetween the host vehicle and the other object. Although in thisembodiment, the determination on collision is performed using speed, anymay be used insofar as collision can be quantitatively evaluated. Forexample, collision energy designated by the size of the mobile object orthe like, the physical amount, such as impulse, or the like may be used.Alternately, economic values may be provided to the mobile object forpeople and property, the amount of economic loss may be estimated, andthe amount of loss may be used.

The collision determination device includes the longest stopover timecalculation unit 16 which calculates the longest stopover time t_(max),at which the mobile object passes through each point of the routecandidate of the host vehicle acquired by the vehicle route candidateacquisition unit 11 when reducing speed, on the basis of the status ofthe mobile object acquired by the mobile object status acquisition unit12. When the shortest arrival time t_(min) calculated by the shortestarrival time calculation unit 15 is smaller than the passage time t ateach point of the route candidate of the host vehicle, and the longeststopover time t_(max) calculated by the longest stopover timecalculation unit 16 is greater than the passage time t at each point ofthe route candidate of the host vehicle, the collision determinationunit 17 determines that there is the possibility of collision betweenthe host vehicle and the other object. With this configuration, sincethe possibility of collision is determined on the basis of a pluralityof movement statuses of the other object, it is possible to determinethe possibility of collision between the host vehicle and the otherobject with higher precision. As a result, it is possible to improvereliability.

Second Embodiment

Subsequently, a collision determination device according to a secondembodiment of the invention will be described. As shown in FIG. 8, acollision determination device 1A of the second embodiment is differentfrom the first embodiment in that a vehicle route candidate correctionunit (route candidate correction means) 18 is provided.

The vehicle route candidate correction unit 18 corrects the routecandidate of the host vehicle acquired by the vehicle route candidateacquisition unit 11. If the route candidate information output from thevehicle route candidate acquisition unit 11 is received, the vehicleroute candidate correction unit 18 partially changes and corrects(replaces) a portion ahead of a portion (predetermined point) to besurely executed by the host vehicle with the route of the host vehiclefrom this point of time as avoidance behavior. Preferably, the vehicleroute candidate correction unit 18 generates a route candidate in whichspeed reduction is made, that is, the speed control quantity is changedin the route candidate represented by the host vehicle route candidateinformation is reduced. Specifically, as shown in FIG. 9A, the vehicleroute candidate correction unit 18 replaces a portion ahead of a portionof the route candidate to be surely executed (a portion which may bechanged in the next calculation period) with a route candidate whentaking avoidance behavior with speed reduction from this point of time.n (1, 2, . . . , n) avoidance behaviors are set in advance, and forexample, heavy braking, normal braking, and the like may be set. Inaddition, as avoidance behavior, sudden steering or sudden accelerationmay be set.

As shown in FIG. 9B, for example, the vehicle route candidate correctionunit 18 corrects a route in accordance with a route, in which the hostvehicle M applies heavy braking, or avoidance behavior, in which thehost vehicle M applies normal braking (for example, −0.1 G), as a routewhich takes avoidance behavior. Avoidance behavior which is selected(applied) by the vehicle route candidate correction unit 18 is replaceddepending on whether a mobile object for determining the possibility ofcollision comparatively observes a condition (traffic classification,road direction, or the like) that movement is permitted, on the basis ofthe determination result information output from the mobile objectdetermination unit 13. That is, avoidance behavior is selected andapplied depending on whether the mobile object is a pedestrian or theother vehicle. The vehicle route candidate correction unit 18 outputscorrected route candidate information representing the corrected routecandidate of the host vehicle to the shortest arrival time calculationunit 15, the longest stopover time calculation unit 16, and thecollision determination unit 17.

If the corrected route candidate information output from the vehicleroute candidate correction unit 18 is received, for each point of theroute candidate of the host vehicle represented by the corrected routecandidate information, the shortest arrival time calculation unit 15calculates, as the shortest arrival time, the time t_(min) at which themobile object can arrive at each point of the route candidate of thehost vehicle at earliest when taking behavior (for example, normalacceleration/deceleration or steering, or suddenacceleration/deceleration or sudden steering) in a behavior range (n: 1,. . . , n) associated with avoidance behavior of the host vehicle in thecorrected route candidate information. The shortest arrival timecalculation unit 15 provides information relating to the calculatedshortest arrival time t_(min) to road data or the road network, andoutputs shortest arrival time information relating to road data or theroad network to the collision determination unit 17.

If the corrected route candidate information output from the vehicleroute candidate correction unit 18 is received, for each point of theroute candidate of the host vehicle represented by the corrected routecandidate information, the longest stopover time calculation unit 16calculates, as the longest stopover time, the time (the latest time atwhich the mobile object passes by each point) t_(max) at which themobile object passes through each point of the mute candidate whentaking behavior (for example, normal acceleration/deceleration orsteering, or sudden acceleration/deceleration or sudden steering) in abehavior range (n: 1, . . . , n) associated with avoidance behavior ofthe host vehicle in the corrected route candidate information. Thelongest stopover time calculation unit 16 provides information relatingto the calculated longest stopover time t_(max) to road data or the roadnetwork, and outputs longest stopover time information relating to roaddata or the road network to the collision determination unit 17.

If the shortest arrival time information output from the shortestarrival time calculation unit 15 and the longest stopover timeinformation output from the longest stopover time calculation unit 16are received, the collision determination unit 17 determines whether ornot the passage time t at which the host vehicle passes through eachpoint of the route candidate is greater than the shortest arrival timet_(min) represented by the shortest arrival time information and smallerthan the longest stopover time t_(max) represented by the longeststopover time information (t_(min)<t<t_(max)). When it is determinedthat t_(min)<t<t_(max), the collision determination unit 17 evaluatesthat there is the possibility of collision between the host vehicle andthe pedestrian, and outputs evaluation result information representingthe effect.

Subsequently, the operation of the collision determination device 1Awill be described with reference to FIG. 10. FIG. 10 is a flowchartshowing the operation of the collision determination device.

As shown in FIG. 10, first, a route candidate of the host vehicle isacquired by the vehicle route candidate acquisition unit (Step S21).Next, the acquired route candidate of the host vehicle is corrected to aroute candidate when taking avoidance behavior with speed reduction bythe vehicle route candidate correction unit 18 (Step S22).

Subsequently, for each point of the corrected route candidate of thehost vehicle, the shortest arrival time t_(min) at which the mobileobject can arrive at each point of the route candidate at earliest whentaking behavior in a behavior range associated with avoidance behaviorof the host vehicle is calculated by the shortest arrival timecalculation unit 15 as the shortest arrival time (Step S23). For eachpoint of the corrected route candidate of the host vehicle, the longeststopover time (the latest time at which the mobile object passes by eachpoint) t_(max) at which the mobile object passes through each point ofthe route candidate when taking behavior in a behavior range associatedwith avoidance behavior of the host vehicle is calculated by the longeststopover time calculation unit 16 as the longest stopover time (StepS24).

The determination on the possibility of collision is made by thecollision determination unit 17 on the basis of the shortest arrivaltime t_(min) calculated by the shortest arrival time calculation unit15, the longest stopover time t_(max) calculated by the longest stopovertime calculation unit 16, and the passage time t at each point of theroute candidate of the host vehicle corrected by the vehicle routecandidate correction unit 18 (Step S25), and it is determined whether ornot t_(min)<t<t_(max) (Step S26). In Step S26, when it is determinedthat t_(min)<t<t_(max), the determination result representing the effectis output (Step S27). In Step S26, when it is determined thatt_(min)<t<t_(max) is not established, the processing ends.

As described above, in the collision determination device 1A, thevehicle route candidate correction unit 18 corrects the route candidateto the route candidate when taking avoidance behavior (for example,heavy braking, normal braking, or the like) with speed reduction at thepoint of time ahead of a portion to be surely executed of the routecandidate of the host vehicle. The collision determination unit 17determines whether or not the time t at which the host vehicle passesthrough each point of the route candidate is greater than the shortestarrival time t_(min) and smaller than the longest stopover time t_(max)(t_(min)<t<t_(max)), and when t_(min)<t<t_(max) determines that there isthe possibility of collision between the host vehicle and thepedestrian. Therefore, for example, when the host vehicle waits forright turn, it is possible to avoid unnatural behavior in which the hostvehicle enters immediately before a right turn waiting point withoutreducing speed and then applies heavy braking to stop. For this reason,the host vehicle can cope with normal behavior, in which the othervehicle travels in a straight line, with a slow acceleration, and evenin the right turn waiting state or the like, natural behavior can betaken with slow deceleration.

In regard to a pedestrian, the host vehicle passes through a sidewaywith the minimum deceleration, and when the pedestrian comes out on aroad, heavy braking is applied to reduce the speed of the host vehicleto “0” before collision. When generating the route candidate of the hostvehicle, the possibility of collision between the mobile object and thehost vehicle can be determined by generating only a portion (initialoperation or the like) to be surely executed, thereby reducing theamount of calculation.

The invention is not limited to the foregoing embodiments. For example,although in the first embodiment, the shortest arrival time t_(min) iscalculated by the shortest arrival time calculation unit 15, the longeststopover time t_(max) is calculated by the longest stopover timecalculation unit 16, and the determination on the possibility ofcollision between the host vehicle and the mobile object is made by thecollision determination unit 17 on the basis of the shortest arrivaltime t_(min) and the longest stopover time t_(max) the possibility ofcollision may be determined only using the shortest arrival timet_(min). Specifically, the collision determination unit 17 determinesthat there is the possibility of collision when t_(min)<t with respectto the passage time t at which the host vehicle passes through eachpoint of the route candidate. In this case, since it is possible todetermine the possibility of collision between the host vehicle and themobile object with a small amount of computation, it is possible tofurther reduce a computational load. For this reason, even whenprediction a few seconds later is required, it is possible to realize adriving support device which controls the host vehicle in real time.

The collision determination unit 17 may determine that there is thepossibility of collision when t_(min)<t and V>V_(m) with respect to thepassage time t at which the host vehicle passes through each point ofthe route candidate. In this case, since the speed of the host vehicle Mis taken into consideration, it is possible to avoid the determinationthat there is the possibility of collision in a state where a pedestrianor the like runs into the host vehicle being parked.

Although in the second embodiment, a route candidate is corrected suchthat the host vehicle takes avoidance behavior (for example, heavybraking, normal braking, or the like) with speed reduction at the pointof time ahead of a portion to be surely executed of the road network,avoidance behavior which is executed by the host vehicle may be set onlyto heavy braking. In this case, the vehicle route candidate correctionunit 18 corrects the route candidate to a route in which the hostvehicle applies heavy braking to stop, and the collision determinationunit 17 determines that there is the possibility of collision whent_(min)<t<t_(max) and V>V_(m). Accordingly, since it is possible todetermine the possibility of collision from the viewpoint that“collision avoidance may be still made by changing a route in the nextcalculation period”, speed reduction is put off while securing thatthere is no collision, and as a result, the host vehicle can travelwhile securing efficiency.

REFERENCE SIGNS LIST

-   -   1 and 1A: collision determination device    -   11: vehicle route candidate acquisition unit (vehicle route        candidate acquisition means)    -   12: mobile object status acquisition unit (mobile object status        acquisition means)    -   15: shortest arrival time calculation unit (shortest arrival        time calculation means)    -   16: longest stopover time calculation unit (longest stopover        time calculation means)    -   17: collision determination unit (collision determination means)    -   20: vehicle route candidate correction unit (vehicle route        candidate correction means)    -   M: host vehicle

The invention claimed is:
 1. A collision determination device comprising: vehicle route candidate acquisition unit acquiring a route candidate of a host vehicle; traveling status acquisition unit acquiring ambient information; other object status acquisition unit acquiring the status of the other object from the ambient information; shortest arrival time calculation unit calculating a shortest arrival time, at which the other object can arrive at each point of the route candidate of the host vehicle acquired by the vehicle route candidate acquisition unit when moving with a predetermined first displacement, on the basis of the status of the other object acquired by the other object status acquisition unit; longest stopover time calculation unit calculating a longest stopover time, at which the other object passes through each point of the route candidate of the host vehicle acquired by the vehicle route candidate acquisition unit when reducing speed with a predetermined second displacement, on the basis of the status of the other object acquired by the other object status acquisition unit; and collision determination unit determining the possibility of collision between the host vehicle and the other object on the basis of the shortest arrival time calculated by the shortest arrival time calculation unit, the longest stopover time calculated by the longest stopover time calculation unit, and the passage time at each point of the host vehicle, wherein, when the shortest arrival time calculated by the shortest arrival time calculation unit is smaller than the passage time at each point of the route candidate of the host vehicle, and the longest stopover time calculated by the longest stopover time calculation unit is greater than the passage time at each point of the route candidate of the host vehicle, the collision determination unit determines that there is a possibility that the host vehicle collides with the other object.
 2. The collision determination device according to claim 1, wherein, when the shortest arrival time calculated by the shortest arrival time calculation unit is smaller than the passage time at each point of the route candidate of the host vehicle, and the longest stopover time calculated by the longest stopover time calculation unit is greater than the passage time at each point of the route candidate of the host vehicle, and when the speed of the host vehicle is higher than a predetermined speed, the collision determination unit determines that there is a possibility that the host vehicle collides with the other object.
 3. The collision determination device according to claim 1, further comprising: route candidate correction unit correcting the route candidate of the host vehicle acquired by the vehicle route candidate acquisition unit to a route candidate when the host vehicle takes avoidance behavior from a predetermined point, wherein the shortest arrival time calculation unit calculates the shortest arrival time at which the other object arrives at each point of the route candidate of the host vehicle corrected by the route candidate correction unit when moving with a predetermined first displacement, and when the shortest arrival time calculated by the shortest arrival time calculation unit is smaller than the time at which the other object passes through each point of the route candidate of the host vehicle corrected by the route candidate correction unit, the collision determination unit determines that there is a possibility that the host vehicle collides with the other object.
 4. The collision determination device according to claim 3, wherein the longest stopover time calculation unit calculates the longest stopover time at which the other object passes through each point of the route candidate of the host vehicle corrected by the route candidate correction unit when reducing speed with a predetermined second displacement, and when the shortest arrival time calculated by the shortest arrival time calculation unit is smaller than the time at which the other object passes through each point of the route candidate of the host vehicle corrected by the route candidate correction unit, and when the longest stopover time calculated by the longest stopover time calculation unit is greater than the time at each point of the route candidate of the host vehicle, the collision determination unit determines that there is a possibility that the host vehicle collides with the other object.
 5. The collision determination device according to claim 1, further comprising: other object route candidate generation unit calculating a route candidate of the other object, wherein the shortest arrival time calculation unit calculates the shortest arrival time, at which the other object arrives at each point where a route candidate which the other object should follow interferes with a route candidate to be taken by the other object calculated on the basis of road information in the vicinity of the other object on the route candidate of the host vehicle acquired by the vehicle route candidate acquisition unit when the other object moves with the predetermined first displacement, on the basis of the status of the other object acquired by the other object status acquisition unit. 